The most widely-used bottle cap is the crown cork bottle cap which was invented by William Painter in 1982. The crown cork bottle cap is made of steel, and as it is used on the vast majority of glass bottles today, the crown cork bottle cap is familiar to most consumers throughout the world. The London Crown Cork Company was established resulting from this invention after which utilization of their bottle caps began in many countries.
A white cap was developed in the U.S. by the White brothers in 1926. The white cap is still used widely today.
However, there are many disadvantages of the above two types of bottle caps. For example, the crown cap cannot be opened without the use of a bottle opener. Also, because it is made of steel, the crown cap can corrode. This corrosion is unaesthetic and unhygienic. With regard to the white cap, although it can be opened without the use of a bottle opener, it cannot withstand gas pressure, limiting the scope of usage of the bottle cap to only bottles of un-carbonated beverages.
To solve these disadvantages, a screw-type PP cap (pilfer proof cap) made of aluminum was developed. The PP cap has the advantage of allowing opening without a bottle opener, but as a result of its construction, a skirt portion of the PP cap often becomes sharp after opening which can cut into a user's hands when the cap is screwed on and off. As a result, a PP cap made of synthetic resin is increasingly replacing the aluminum PP cap. However, the screw-type PP cap made of synthetic resin is difficult to open, and during the twisting packaging process, an extreme top end of a bottle can become damaged.
Another type of bottle cap is the ring pull cap made of metal. The ring pull cap is extensively used in the U.S. and Japan. However, the ring pull cap can also become sharp after opening like the aluminum PP cap, it can not reseal the bottle after opening, and due to the thinness of the ring pull cap, it cannot withstand pressure created in carbonated beverages.